The graph of f has no removable, infinite, or jump discontinuities. This means the graph has no holes nor vertical asymptotes and can be traced without ever lifting your pencil.
Work Step by Step
If f is continuous on ($-\infty$,$\infty$), that means it is continuous on everything except $-\infty$ and $\infty$. $-\infty$ and $\infty$ aren't real numbers. Therefore, f is continuous at all real numbers and as such, there are no discontinuities in the graph of f.